Pre-combustion CO2 capture & storage technology is applied to CO2 source (pre-combustion or pre-utilization) capture & storage of synthetic gas (syngas) application fields such as integrated gasification combined cycle (IGCC) power systems, synthetic natural gas (SNG), or coal to liquid (CTL) fuel, and selectively captures and stores only CO2 after shifting carbon monoxide in coal syngas into hydrogen and carbon dioxide through a water-gas shift reaction (CO+H2O→CO2+H2). Conventional commercial pre-combustion CO2 capture & storage processes include Selexol, Rectisol and so on, employing physical sorbents. However, these conventional processes have several problems of low heat efficiency due to low-temperature operation, consumption of a large amount of recycled energy, necessity for additional energy for CO2 compression, complexity in process design, and so on. In addition, the polymer membrane technology that is nowadays actively researched enables high-temperature high-pressure operations, thereby achieving high-energy efficiency, but has a problem of difficulty in application to large-scale industries due to a low yield. In order to overcome disadvantages of the existing pre-combustion CO2 capture & storage technology, the fluidized bed sorption enhanced water gas shift (SEWGS) process employing dry CO2 sorbents and catalysts is being recently developed.
Among patents related to the conventional pre-combustion CO2 capture & storage technology, U.S. Pat. No. 8,207,086 reported that layered nano carbonate was developed as a medium-high temperature CO2 sorbent, which demonstrates high activity in capturing CO2 at a temperature above 600° C.